


Everything Changes

by lupwned



Category: Ghostbusters (2016)
Genre: F/F, Feels full steam ahead, Fluff, Kid Fic, Romance, Yep it's an unexpected parenting fic, slowburn
Language: English
Status: In-Progress
Published: 2016-09-21
Updated: 2017-04-04
Packaged: 2018-08-16 10:43:19
Rating: Not Rated
Warnings: No Archive Warnings Apply
Chapters: 5
Words: 7,111
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/8099077
Author URL: https://archiveofourown.org/users/lupwned/pseuds/lupwned
Summary: Two tiny hands, a pair of eyesAn unsung melody is mine for safekeepingAnd I will guard it with my lifeI'd hang the moon for it to shine on her sleepingStarting here and starting nowI can feel the heart of howEverything changes ~ "Everything Changes", Sara BareillesWhen the Ghostbusters moved into the abandoned New York City firehouse, the last thing they’d expected was for someone to still treat it as a functioning station. Someone clearly missed the memo, however, because sitting on Erin, Abby, Patty and Holtzmann’s front doorstep is an infant, swaddled in a bright red blanket.





	1. Chapter 1

**Notes for the Chapter:**

> Yep, I'm trash and keep writing more fics. Save me.

_12 hours_. Erin blinks a few times and yawns. She turns to the digital clock on her desk and squints. The numbers are blurry, Erin bleary eyed from exhaustion, but she manages to make out the time when she truly focuses.

1:23am. 12 hours.

She’s worked on equations for almost 12 hours straight, a few bathroom runs and a handful of blueberries her only real breaks, and her brain feels as though it is about to melt out of her ears. Long overdue for some rest, Erin closes the top of her laptop and tucks it in her dark brown briefcase. It’s Friday – technically Saturday now, she reminds herself – and despite the fact that the weekend is upon her, she knows she’ll continue to work throughout it, and, as such, she packs her charger and hand written notes alongside her computer. She stretches in her seat, lifting her arms up in the air above her head and rolling her neck in careful circles, her achy bones cracking loudly.

Ready to head home to her apartment for the weekend, Erin grabs her briefcase and coat and makes her way out of her makeshift office in the firehouse, turning back momentarily to flick the light switch off. Her heels click against the tile of the hallway, accented by the quiet stillness of the enormous building. It bustles with laughter and discoveries during the day, but at night, an uncomfortable silence engulfs the Ghostbusters’ headquarters. Erin doesn’t make a habit of staying late – in fact, she tries to avoid it at all costs, instead opting to work from home in the evenings if they aren’t on a bust – but tonight is an exception; she doesn’t know how Holtzmann does it, regularly staying throughout the night into the early morning hours.

Holtzmann. Erin stops in front of the laboratory, noticing a beam of light shining from below the doorframe. It’s not exactly shocking Holtzmann is still here, but the cacophony of science and Pringles needs sleep just like the rest of them, and Erin decides to take it upon herself to ensure that Holtz does just that. “Holtz?” She opens the door carefully, peeking into the lab and praying under her breath that she’s not about to have her eyebrows singed off for the _third_ time this month from one of Holtzmann’s experiments.

“Gilbert.” Holtzmann pushes her yellow-tinted goggles up her forehead to rest on the top of her head, then smiles. “What are you still doing here?”

Erin chuckles. “I could ask you the same thing.”

“Touché,” Holtzmann responds before turning back to the large pile of metal and wires in the center of her desk. “I’m trying to put the finishing touches on this upgraded containment unit.” She taps the right corner of the metal box with the top of a screwdriver.

“So far so good?” Erin rests her hip against the doorframe, suddenly realizing just how sleepy she truly is.

“Not quite,” Holtz sighs, tossing her tools aside and running both hands through the knots in her frizzy hair. “Probably best to call it a night.”

Erin nods in agreement and watches as Holtzmann gathers her belongings – an old, tattered trench coat with several small holes in the arms, a yellow notepad with handwriting so messy Erin’s convinced even _Holtz_ isn’t able to read it, her smartphone, and some empty Tupperware containers that appear to have begun to grow some experiments of their own.

Maybe it’s the exhaustion, the fact that she’s bleary-eyed and slightly delirious, but Erin feels warm and giddy as she watches Holtzmann. Her gold curls almost glow underneath the soft light of the lab; if Erin believed in that sort of thing, she might even liken Holtzmann to an angel – a swearing, silly, Pringle-chomping angel.

“I have to shut everything down, so I’m going to be a minute,” Holtzmann instructs, pulling Erin out of her odd daydream. “I’ll meet you downstairs?”

Erin nods, continuing down the hallway and bouncing down the stairs, her heels clanking against the metal. Most of the lights are already off – Patty and Abby making a habit of turning them off as they leave to conserve energy – and the emptiness of the firehouse is only amplified by the silence and darkness. Although she’s a Ghostbuster, there’s something slightly terrifying about the firehouse at night. Erin suddenly feels incredibly uncomfortable, goosebumps prickling the back of her neck and behind her ears. She glances up toward the staircase, shuffling back and forth nervously as she waits for Holtzmann to join her near the front entrance.

High-pitched. That’s the only way Erin can describe the noise that starts soft and grows in intensity, bouncing off the empty walls of the first floor. For a moment, Erin thinks it’s simply the whine of a screwdriver upstairs, but she quickly realizes it’s coming from the opposite direction of Holtzmann’s laboratory.

Erin’s seen horror movies. She’s watched plenty of physiological thrillers to know that what she’s doing is not exactly a smart idea, would even call it asinine were she to witness someone else doing it. Alone in the dark, she tiptoes toward the sound. The whine grows stronger and stronger until Erin fully recognizes what she’s hearing – crying. Not just _any_ crying, though.

With newfound confidence, Erin throws open the front door.

When the Ghostbusters moved into the abandoned New York City firehouse, the last thing they’d expected was for someone to still treat it as a functioning station. Someone clearly missed the memo, however, because sitting on Erin, Abby, Patty and Holtzmann’s front doorstep is an infant, swaddled in a bright red blanket.

For a moment, Erin doesn’t know how to react. A million different scenarios rush through her head, and it isn’t until she hears Holtzmann’s voice call to her that she comes to once again.

“What is that noise?” Holtzmann asks, bounding down the steps two at a time.

“A baby,” Erin says, hushed and breathy, almost a whisper. She tosses her briefcase and coat down on the ground and kneels, pulling the infant inside. It’s little face and cheeks are bright red from crying, matching the cloth it’s wrapped in.

“Holy hell.” Holtzmann rushes to Erin, glancing around the physicist’s shoulder to get a good look at their visitor. “Did you see who left it here?” She glances toward the front door. “Did it have a letter or a tag or…”

“It’s a baby, not a puppy, Holtzmann.” Erin carefully stands, then rocks back and forth, trying to remember the last Gilbert family reunion where she had been given the awkward task of caring for her sister’s newborn, despite the fact that she had no idea what she was doing and the most maternal experience she’d had up until that point was growing a flower from a seed, which promptly died a week after it bloomed.

Qualified for motherhood, regardless of the circumstance, is not exactly how Erin Gilbert would describe herself.

“Hi, baby,” Holtzmann coos, tickling the infant’s cheek with her index finger. It looks up at her with wide, blue eyes and babbles. “I’m Mama Holtzmann, and this is Mommy Erin.” On cue, the baby laughs.

Erin wrinkles her forehead and opens her mouth, trying to formulate some kind of protest and needlessly explain to the infant who clearly doesn’t understand English that she’s not its mother, that Holtzmann isn’t its mother, but there’s something about the thought of the three of them together as an odd family that makes Erin feel…well, feel _something_. She leans down carefully and places a gentle kiss on the baby’s forehead. In the morning, they’ll call the police or the hospital or whatever you’re supposed to do when someone leaves a child on your doorstep. Thank goodness for Google.

Holtzmann gently musses the baby’s hair and smiles, wide. “Welcome to the Ghostbusters, kid.”


	2. Chapter 2

Erin’s inclinations are quickly confirmed - she doesn’t have a maternal bone in her body. It doesn’t take long before the infant in her arms begins to squirm and fuss, a screeching cry piercing the otherwise quiet firehouse. Chubby cheeks tint pink, then full on red as the baby’s crying intensifies. Bouncing around, Erin looks around with panic, trying to figure out what exactly she can do to get this tiny human to _stop crying_. For the moment, it’s just the two of them; Erin had sent Holtzmann down the street to the local convenience store to get a package of diapers and other baby necessities to at least last them through the night. Now, with a baby shrieking in her ears, she wishes she’d volunteered herself as baby-shopping tribute.

“I may have had to fight off a horde of zombies, but fear not, m’lady. I am here.” Holtzmann rushes into the room, several plastic shopping bags draped across each arm. It’s significantly more than they need to take care of a baby for one night, but Erin’s too exhausted to argue at this point.

“Zombies?”

“What else would you call anyone who shops at CVS at 2:30 in the morning?” Holtzmann tosses her bags on a nearby counter and swoops in front of Erin, reaching for the infant who is still crying wildly in her arms. “Mama H has got you,” Holtz coos, her eyes wide and her mouth curled up in a large, playful smile. For the first time in almost an hour, a sense of calm fills the room; Erin’s ears ring from the sudden silence.

“Mama H?” Erin asks with a raised eyebrow.

“Well, it’s easier to say than Mama Holtzmann, isn’t it?” Holtzmann tickles behind the baby’s ear with her index finger, which promptly causes it to giggle in that infectious way that only babies can.

“Right.” Erin shuffles awkwardly over to the plastic bags filled with diapers, formula, bottles, pacifiers, blankets, and an array of other items that could be easily classified as overkill. “Christ, Holtzmann, Do we really need all of this?”

Holtzmann simply shrugs. “Can you grab me the blanket, wipes and a diaper?”

Erin nods and gathers the items Holtz asks for. With Holtzmann’s instruction, she lays one of the blankets – pastel yellow in color with a green frayed trim – across the living room sofa, along with the package of baby wipes and diapers. Wordlessly, Holtz sets the infant in the center of their makeshift changing table. Erin watches, amazed, as Holtzmann changes its diaper with a gentle, careful touch. “Gentle” and “careful” aren’t exactly words that Erin finds herself regularly describing Holtzmann as, but the last two hours have been so crazy that the Queen of England bursting through their front door wouldn’t surprise her at this point.

“There we go.” Holtzmann snaps the baby’s onesie back in place. “All clean!” Voice raised at least an octave, she makes a funny, exaggerated face while wiggling her fingers on either side of her head. The child watches, transfixed, switching back and forth between being silently amazed and giggling wildly at the engineer playing peek-a-boo. “Er Bear, can you fix Rosie a bottle?”

Erin promptly turns back towards the collection of baby items, but stops on her heels. “Rosie?”

“Mmhm. That’s her name. Rosalind. After Rosalind Franklin.” Holtzmann scoops the baby up from the couch and into her arms. “What do we think, Rosie? Do we like that name?”

Rosie grabs Holtz’s left hand and sticks it into her mouth, a sticky pool of drool dripping slowly down Holtzmann’s arm.

“I’ll take that as a definite yes.”

Erin laughs, then grabs the double set of plastic baby bottles, washing one of them in a nearby sink. Once clean, she fills the bottle up with 4 ounces of water, followed by two scoops of dry formula. When the powder disintegrates, Erin goes to heat the bottle up in the microwave, only to have Holtzmann gasp and rush to her as though she were about to touch one of her very nuclear, very dangerous experiments. Balancing Rosie in one arm, she grabs the bottle from Erin’s hand and looks at her with a shocked expression. “Microwave is a no-go there, mommy,” Holtz instructs, running the tap until it is just above lukewarm. “Microwaves don’t heat evenly. She could get burned.”

Embarrassment creeps up Erin’s neck and behind her ears. “I…” She looks at her feet for a moment, then back at Holtz. “I didn’t know. Sorry.”

Holtzmann moves Rosie so she’s fully cradled in her arm and begins feeding her; the baby, clearly hungry, suckles on the nipple with glee. “It’s ok. It takes time to learn these things.” She kisses Rosie’s hair as she continues to gulp down her milk.

Erin rests her hip against the corner of the counter and crosses her arms over her chest. “How do you know so much about this? I don’t picture you as the maternal type.” Erin smiles. “It suits you, though.”

Erin’s certainly not exaggerating. With Rosie cradled in her arm, Holtzmann’s almost glowing, her eyes and smile bright with excitement. Their surprise guest seems to have sparked a flame in Holtz that is unexpectedly beautiful. Simply put, Erin can’t help but stare.

“I grew up in the system,” Holtzmann explains, her voice soft, slightly shaky. “I had a lot of brothers and sisters. It sorta just came with the territory.”

“Oh Holtz, I’m sorry. I didn’t.” Erin scratches the back of her head.

Holtzmann raises her hand to stop her. “No need. All good.” She smiles.

Sucking nothing but air at this point, Rosie spits the bottle out and bats it away. With her tiny, balled up fists, she rubs her eyes and yawns loudly with a cute little squeak that makes even Erin’s heart swoon.

“I think it is _waaaaaay_ past someone’s bedtime.”

“Yeah, mine too,” Erin jokes while she runs her fingers through her hair. “I’m going to go change into my pajamas. You two get settled and I’ll be right back down.” She walks to the staircase and hops up a few stairs before stopping. “Need anything from upstairs?”

Holtzmann shakes her head. “Just you,” she teases with a wink.

It only takes Erin a few minutes to change into the dark blue tank top and bright orange pajamas pants she leaves at the firehouse for times when it just makes more sense to stay the night. She pulls her hair up in a ponytail using the black band she keeps on her wrist, then steps into the bathroom to check her appearance before making her way back downstairs. Holtzmann’s never seen her like this before – clean faced and sleepy and casual - and, for some reason she can’t immediately put her finger on, it’s absolutely nerve-wracking. For a few moments, she fusses with a few strands of hair that stick out from her ponytail, then leaves the bathroom toward the wooden staircase. Two by two, she moves down the stairs. “Holtz, I’ll take the couch if you want to-“

It appears their sleeping arrangements have been decided upon when she comes to find Holtz sprawled out across the black sofa, Rosie curled up on her chest with a protective arm around her. The pair snores in tandem, drool trickling out of the corner of each of their mouths. With a smile she has little control over, Erin curls up at the far end of the sofa next to Holtzmann’s feet where a little space still remains, and watches. She knows if anyone else was there, it would come off incredibly creepy, but she can’t stop staring, memorizing the way Holtzmann’s nose scrunches and her breathing hitches occasionally as she dreams. “Don’t let the bed bugs bite,” Erin sings softly before closing her eyes and letting her exhaustion take over.

**Notes for the Chapter:**

> As always, comments and kudos are always appreciated. Thanks to everyone who has read :)


	3. Chapter 3

“Please tell me Holtzy did not steal someone’s child.” Patty steps carefully into the living area of the first floor of the firehouse with a coffee in one hand and a box of donuts in the other.

“Finally have enough for my blood sacrifice.” Holtzmann grins wildly at Patty, then at the baby in her arms, who promptly erupts in a fit of giggles.

“Ok, but seriously,” Patty glances over to Erin, who sits at the kitchen counter eating a bowl of oatmeal and swiping through the morning news on her iPad. “Where did this baby come from?”

“Doorstep,” Holtz answers despite the question not actually being directed at her.

Without a word, Patty looks once more in Erin’s direction.

“She’s not lying.” Erin finishes her breakfast, swallowing the last bite of Quaker Oats slowly, and hops off the kitchen stool. “We were here late and I heard something-“

“You two were here. Late. Alone.” Patty squints her eyes and smirks. “ _Together_.”

“Irrelevant.” Erin tries to swallow the heat of embarrassment that creeps up her neck and into her cheeks. “I was-“

“Mmmmmhmmm.” The smirk on Patty’s face only grows, pearly and white and suspicious.

“I was just about to leave when I heard a baby crying. I walked outside and that’s when I found Rosie-“

“Rosie?” Patty shakes her head and laughs under her breath.

“Yeah, that’s what I’ve named her!” Holtzmann cuts in from across the room.

Out of the corner of her eye, Erin notices Holtz play eating Rosie’s fingers, the noises pouring from the engineer’s mouth akin to a certain Cooke Monster on Sesame Street. Once again, the newest Ghostbuster erupts into laughter.

“The paranormal is pretty damned terrifying, but if we’re suddenly going into the babysitting business, even that is too scary for me.” Abby walks into the room and tosses her bag onto the floor, stopping short in front of Erin and Patty. “Why the hell is there a baby here? And, more importantly, who thought it was a good idea to leave Holtzmann in charge of it?”

Letting out a frustrated sigh, Erin starts over and explains yet again about Rosie’s arrival on their doorstep.

“Have you called the police?” Abby asks, walking over to Holtzmann to get a closer look at their first _corporeal_ intruder.

“It was late and Holtzmann had a pretty good handle on the situation,” Erin explains.

Abby looks at Holtzmann with a raised eyebrow. Before she gets the opportunity to say anything, Rosie grabs for Abby’s black, thick-rimmed glasses with tiny - yet mighty - fists. In a swift, quick movement, Rosie finds herself a new toy, sticking one of the temples into her mouth and promptly covering the lenses with sticky, bubbly baby drool. She sucks happily on the plastic, looking up at Holtzmann with a lopsided smile and wide, blue eyes.

“Oh come on,” Abby grumbles, snatching her glasses out of Rosie’s hands.

A moment later, the shrill sound of crying fills the firehouse, echoing through the expanse of half-empty rooms and hallways.

“For the love of all that is holy, please make it stop,” Patty grumbles, rubbing her head with her index fingers.

“Erin, it’s morning now. Call the police,” Abby instructs. “Someone’s probably looking for her-“

“ _No one_ is looking for her,” Holtzmann interrupts sharply. Her voice shakes slightly and the anger laced in her words does not go unnoticed by Erin. “Someone who leaves a baby on a doorstep does not expect to come back for it.”

“Holtzmann, we need to do the right thing.” Abby pushes her glasses up the bridge of her nose. “The best place for her is with the police or-“

“No, the best place for her is here. _We_ can take care of her.”

“Holtzy, this ain’t no place for a baby.” Patty steps over to Holtz and tries to comfort her, resting a hand just below her shoulder, but Holtzmann wants nothing to do with it, shrugging her away. Instead, she holds Rosie close to her chest and looks at Erin, begging for her to stick up for her, for _them_.

Erin, with an immediate tinge of regret, says nothing.

“Come on, sweetie,” Holtzmann coos softly. Before Erin has the opportunity to make things right, Holtz turns on her heels and heads upstairs with Rosie in toe. A moment later, the sound of the laboratory door slamming shut bellows through the building like a series of exclamation points at the end of a sentence, loud and sharp and emotional.

**-X-X-X-X-**

Erin hasn’t always been the best at gauging emotional situations or choosing her battles wisely, but even _she_ knows that approaching Holtzmann immediately after she stormed off would not have ended well between the two of them. Instead, Erin returns to her research upstairs to distract herself from the situation at hand.

Chewing on the end of her pen, Erin contemplates the options before them. To gather accurate results, Erin hypothesizes, weighing all the possibilities, all the pros and cons of each scenario. They _could_ call the police and give the baby up, where she could possibly be returned to her family. On the other hand, she could be put into foster care once the dust settles, possibly bouncing from home to home with no real sense of normalcy in her life.

In less than 24 hours, Holtzmann has surprised Erin with her soft, tender touch, caring for Rosie as though she were her own without hesitation or fear or doubt. If someone truly did give this little girl away like old furniture at the curbside, what harm is there in keeping her, even if it’s only temporarily, with someone who wants nothing more than to love and provide for her?

But what if her family didn’t purposely give her away? Erin taps her pen absentmindedly against her desk as the array of scenarios swirl in her head. What if she was kidnapped, had been unrightfully taken away from people who truly _do_ care about her and just want her to return home?

Erin groans and rests her head in her hands. She can feel a tension headache forming, her sinuses tight and the vein at her temple beginning to throb. There’s no easy solution, Erin quickly realizes, but there is a _right_ one – a _legal_ one.

With her heart thundering in her chest, Erin moves from her desk to the hallway outside Holtzmann’s lab. Inconspicuously, she cracks the door open just slightly, just enough to peek inside at the usual chaos of Holtzmann’s workspace. Routine has conditioned Erin to expect the worst, but she’s surprised to find Holtzmann in the center of the room with Rosie bouncing in what appears to be a makeshift swing. It looks almost identical to one easily purchased at Babies R Us, but there’s a unique touch that clearly signals it’s a Holtzmann original.

Erin watches with her mouth slightly open, her breathing shallow and quiet to prevent Holtz or Rosie from noticing her. Erin feels like a Peeping Tom, creeping in on a moment that Holtzmann assuredly thinks is in the safety and solitude of her own space when the engineer begins to sing softly and sweetly to Rosie, who watches transfixed, almost mesmerized by the lulling sound of Holtzmann’s voice.

_“Catch a falling star and put it in your pocket_  
_Never let it fade away_  
_Catch a falling star and put it in your pocket_  
_Save it for a rainy day.”_

Holtzmann smiles, big and beautiful and dimpled, as she presents Rosie with another item – a hand crafted rattle with stars at the end. The edges are dulled and curved and made of cloth to prevent any injury; Erin’s not quite sure what the other side is filled with to cause the rattling, but she’s in awe of all Holtz has created in the little time she’s been alone in her lab.

As Holtz continues to sing, Erin finds her resolve fading away with each note. Holtzmann looks so happy, overjoyed in a way Erin’s quite certain she’s never seen from her before. Erin doesn’t know whether she could survive the devastation of being the one responsible for Rosie being taken away.

Tiptoeing away from the door and back down the hallway to her office, Erin pulls her cell phone from her pocket and pulls up her contacts. Swiping up a few times, she reaches the person she’s looking for, tapping on their name to initiate a call. It takes a few rings before a feminine voice answers.

“Hello, Jennifer? It’s Erin Gilbert.” She leans her hip against her desk and looks up at the ceiling. “Remember when you said if we need anything, anything at all, we should call you?” It takes a few quiet but deep breaths before Erin has the nerve to continue. “I have a favor to ask of you.”

**Notes for the Chapter:**

> Work has been super, _super_ crazy, so I apologize for the delay. Comments and kudos make the author smile :)
> 
> Come follow me on Tumblr or Twitter and say hi!
> 
> Tumblr: awomanontheverge  
> Twitter: @pattilupwned


	4. Chapter 4

**Notes for the Chapter:**

> Happy Halloween (if you celebrate) from Erin, Holtz and Rosie. 
> 
> For your reference: 
> 
> [Rosie's Costume](http://thumbs3.ebaystatic.com/d/l225/m/mmaxc08U_ZeDkub0Y3Uk6UQ.jpg), [Holtzmann's costume](http://images.halloweencostumes.com/products/1941/1-1/mens-deluxe-mad-hatter-costume.jpg), and [Erin's costume](http://www.queenofheartsdresscostumes.com/images/deluxe-queen-hearts-costume.jpg)

“I will see what I can do.” It’s the last thing Erin hears before the call disconnects and the flatline buzz of the phone rings in her ear. It’s not the definite yes or no Erin hoped for, but she also realizes it’s going to take some time and finagling on the local government’s part to swing this in their favor. _‘I’ll see what I can do’_ is a whole lot better of an outlook than a harsh _‘no’_ , so Erin supposes she’ll take what she can get.

In the aftermath of her recent call with Jennifer Lynch, Erin slumps in her desk chair and tries to prepare for a much-needed conversation with Holtzmann. She practices a mini-speech under her breath, her hands waving animatedly as she does so, only stopping when a cold pair of hands squeeze her shoulders. Erin jumps what feels like several feet in the air and clutches her chest in fear.

“I’m going to kill you,” Erin curses, gasping to catch her breath.

“You’d never,” Abby teases with a smile. She sits on the edge of Erin’s desk and looks down at her, her thick-rimmed glasses sliding down the bridge of her nose ever so slightly. “Did you make the call?”

Erin nods slowly.

“And the verdict is?”

Erin swallows. “I’m not…. _entirely_ sure yet.”

Abby starts to argue, but Erin stops her with a raised hand.

“I called Jennifer Lynch.”

Abby only gets out a short squeak before Erin interrupts her again.

“Before you say anything else, hear me out. She’s going to look into recent missing children cases, as well as any other clues as to where Rosie may be from and who she may be. We’ll have to cooperate with the law enforcement, but in the meantime, she’s going to try and pull some strings to let Rosie stay here for a bit. Holtzmann clearly knows what she’s doing, and it…” Erin glances out her office door toward the hallway, looking but not _really_ looking, doing something more akin to daydreaming. She clears her throat and looks at Abby again. “It seems to make her really happy. And all of us will be here to pitch in. It will be good.” Erin’s not sure whether she’s trying to convince Abby or herself of it.

“I’ll help, but I’m forever opting out of diaper duty. I’m also not waking up for 3am feedings.” Abby crosses her arms over her chest. “Those are my terms.”

Erin wants to say something snarky back, that she’s only _one_ out of four votes, but it’s been a crazy twenty four hours and Erin’s not exactly in the mood for arguing. Instead, she nods in agreement, then pushes past Abby, making her way down the hall to Holtzmann’s lab.

Erin peeks inside and knocks hesitantly on the doorframe. “Can we talk?”

Holtzmann looks over her yellow lenses at Erin and grunts, immediately returning to focus on the series of metals, bolts and screws on her workbench.

“Where’s Rosie?”

“Oh, _now_ you care,” Holtzmann says sharply, splaying her palms against the table and looking over at Erin with a look of irritation across her face. They keep eye contact for a few moments, an angry tension crackling through the room, and Erin has to swallow an odd feeling of inappropriate excitement that buzzes in her chest. “She’s over there,” Holtz eventually concedes, pointing to the corner where Rosie sleeps in her swing; it appears to rock slowly on a timer, with just enough movement to keep the infant content and sleeping comfortably.

“Oh.” Erin stands awkwardly, shifting her weight back and forth a few times before grabbing a nearby chair to sit next at Holtzmann’s workspace. “I spoke to Jennifer Lynch.” Erin pauses to see if Holtzmann says anything, or shows even the slightest emotion; frustratingly, Holtz keeps straight-faced and focused on the material in her hands. “She says she’s going to look into Rosalind’s case, but that for the time being, Rosie can stay here as long as we’re willing to care for her.”

That gets Holtz’s attention.

“We’ll have to give them regular updates about how she’s doing, and cooperate with their investigation, but for now, she’s a junior Ghostbuster.”

Holtzmann smiles, and Erin’s world stops. She tries to come up with some sort of apology for not sticking up for her earlier, but Erin doesn’t have the chance to before Holtz’s speaks.

“I’m sorry for being so…” Holtzmann looks over at Rosie, choosing her words carefully with young ears around, “ _unpleasant_. This whole thing is a really difficult and sensitive subject for me, and I…” She scratches at the back of her head with her screwdriver.

“Don’t worry about it.” Erin waves her hand dismissively.

Holtzmann’s smile widens and her dimple deepens with excitement. “So she’s staying?”

“For now,” Erin says with a chuckle. “I’m not sure how long it will be but for now, yes, she is staying.”

Holtzmann steps away from her desk and toward where Erin is seated, closing some of the space between them. Erin can smell oil and metal and Jergens moisturizer – Holtzmann’s signature scent that’s the percent concoction of abrasive and sweet and something Erin would _bottle_ if she could. Staying seated, she looks up at Holtzmann, who simply stands there, smiling at her, and _Christ_ , all Erin can do is stare at Holtzmann’s lips, her own twitching at the thought of…

“Thank you, Erin.” Holtzmann sticks her hand out.

Erin’s forehead wrinkles for a second, unable to deny the tinge of disappointment at a handshake and not a….Erin shakes her head and smiles as she takes Holtz’s hand in hers, giving it a little lingering squeeze before the handshake ends. “You’re welcome, Holtz.”

“This means we can get started, then!” Holtzmann exclaims, rushing over to one of a series of cabinets in the corner of the room. “I’ll have to do a little searching, and maybe make a quick stop at the craft store, but then we should be all set to-“

“What are you talking about?” Erin follows Holtzmann and cocks her head to the side.

Holtzmann pulls a few bolts of fabric from the top shelf, as well as a box of miscellaneous buttons and bows. Holtz turns to Erin and squints, her eyes slowly dragging up and down Erin’s body, watching, analyzing. “What’s your dress size?”

**-X-X-X-X-**

“Smile, smile, smile!” Patty sings, snapping dozens of pictures with her iPhone. “Holtzy, hold her in front of you so I can get a better one.”

Holtzmann does so with a nod, shifting Rosie in her arms so she’s directly in front of her. Holtz adjusts the black ribbon in the infant’s hair and tugs down on the bottom of her blue and white ruffled dress, more difficult than it seems as Rosie squirms uncomfortably to try and grab the large, maroon bowtie around her new foster mother’s neck.

“Rosie, stop that,” Holtzmann scolds softly.

Rosie squirms a bit more but lets go of the fabric. Instead, she blinks up at Holtzmann with big blue eyes, seemingly mesmerized by bright orange curls peeking out of the large brown hat on the top of Holtz’s head.

“Mama H looks silly, doesn’t she?” Holtzmann makes an exaggerated face, which immediately makes Rosie giggle.

Abby jogs down the staircase, stopping halfway and clearing her throat to get Patty and Holtzmann’s attention. Dressed as the White Rabbit, she tugs on her red vest and mimes a trumpet. “I present to you, the Queen of Hearts!” Abby adds in a touch of fanfare, then points toward the top of the staircase.

Erin’s almost unrecognizable in the large, custom-made Queen of Hearts gown. Holtzmann had worked on it agonizingly, neglecting her Ghostbusting duties to make sure it was complete in the short time they had before Halloween. Every ribbon, every heart, every bow had to be in perfect place before she’d even allowed Erin to see it.

“How do I look?” Erin asks with a spin. When she’s facing the team again, she sticks her chin up and stands straight to put on a regal façade for a few moments, then softens, smiling at Abby, then Patty, and then finally Holtzmann, who’s staring up at her in a way that makes her heart race. She’s the Queen of hearts tonight, but even _she_ can’t control hers when Holtzmann looks at her _that way._ Being the subject of Holtz’s attention makes her so frustratingly nervous. She smooths a few wrinkles on the skirt of her costume to steady her trembling hands.

“Baby, you look hooooot,” Patty compliments. “Come down here and stand next to your Hatter!”

“She’s not my….” Erin shakes her head and carefully descends the stairs. It’s not an easy feat in her costume and bright red heels, but she keeps her head in the air and moves with nothing less than the beauty and grace of a Queen. “Off with your head!” Erin teases when she finally gets a good look at Rosie, dressed as Alice in baby blue and white. She tickles the baby’s cheek with a red-painted fingernail, then looks at Holtzmann, who manages to look absolutely stunning in brown and purple polyester and stripped back and white linen pants. There’s charcoal black eyeliner and mascara spread across Holtzmann’s eyes and hot pink stain on her lips; Holtzmann is absolutely gorgeous without makeup, but the addition of it only accents the bright blue of her eyes and the curve of her cheeks, and Erin has to look down at her shoes when she realizes just how long she’s been staring.

“The Mad Hatter at your service.” Holtzmann bows a little at the waist, or as best she can with Rosie in her arms. “You look…”

Erin swears she hears Holtz’s breath hitch just a little as she eyes her up and down, taking particular interest in her corseted waist and the way her breasts practically spill over the top of the heart-shaped bodice. With Holtzmann being the seamstress, Erin knows that particular feature wasn’t by accident.

“You look…good.”

Erin laughs. “I’ll take that as a compliment, I suppose.”

Holtzmann simply nods awkwardly, then shifts her attention to Rosie, who’s started to squirm and reach for Erin. “Want to take her?”

“Oh, I don’t…I don’t know if I should-“

Holtzmann carefully sets Rosie in Erin’s arms. The baby settles, then babbles up at Erin, grinning. Moments later, she nuzzles her face against Erin’s chest.

Abby, Patty and Holtzmann burst out laughing.

“Smart kid,” Holtzmann compliments under her breath, but Erin still manages to hear it.

“Alright, let’s get a family picture!” Abby motions for Holtz and Erin to get together, and Patty just smiles on, admiring the view. On the count of three, the camera light flashes and Abby snaps several pictures of the Wonderland team. “Alright, now just the two of you!” Patty walks over and carefully takes Rosie from Erin’s arms.

“Oh, I…ok.” Erin moves a bit closer to Holtzmann.

“Come on, Erin, Holtzmann doesn’t bite.” Abby looks over her phone and motions for the pair to get even closer.

“Only if you asked me to,” Holtzmann whispers in Erin’s ear.

Erin almost chokes on her own spit. It doesn’t help that Holtzmann’s wrapped her arm around her corseted waist, pulling her against her so their sides are touching. Holtz is wearing some type of spicy, cinnamon, Halloween-y perfume that makes Erin’s head spin; it’s festive and intoxicating, appropriately Holtzmann.

They stand together for what feels like an eternity, Abby snapping away with her iPhone, until Rosie begins to fuss loudly in Patty’s arms, desperately trying to escape Patty’s embrace. “I think someone wants her mom. Or moms,” Patty teases with a wink.

“Alright, let’s get this show on the road! Trick or Treating only lasts a few hours. Gotta make sure to hit the businesses handing out the good shit.”

Erin rolls her eyes and takes Rosie from Patty’s arms, balancing her on her hip. “You ready to get spooky, Miss Alice?”

“If it’s one thing I’m good at, it’s gettin’ spooky!” Holtzmann says excitedly. She reaches for Erin’s free hand, the one not holding Rosie, and tugs her to the front door of the station. “Let’s roll!”

**Notes for the Chapter:**

> Comments and kudos make the author smile :)


	5. Chapter 5

**Notes for the Chapter:**

> Happy Holtzbert week!

Trick-or-treating goes surprisingly well. The local businesses and neighbors absolutely adore Rosie and pile on the candy by the handful. Holtzmann is overjoyed by the end of the night, dramatically saying that she will accept the burden of eating all of the candy.

By the time they get back to the firehouse, Abby and Patty have already left for the night. Rosie is fast asleep, drooling across the purple fabric of Holtz’s costume. Holtzmann tiptoes upstairs, trying not to wake the infant; Erin kicks off her heels at the bottom of the staircase and follows only a few steps behind.

“Are you gonna change her?” Erin whispers.

Holtzmann shakes her head. Carefully, she removes the black clip-on bow from Rosie’s head, then sets the snoozing baby into her crib, carefully and lovingly built by a certain engineer in-between her Halloween preparations. Holtzmann hovers next to the crib for a minute, waiting for Rosie to stir, but the night has been exhausting for all of them, and she sleeps without a fuss.

Erin watches in the doorway with the softest hint of a smile. The lights to the lab are all off, but the moon and never-resting city cast Holtzmann in a shadowy, blue-tinted glow. Her once-pinned curls – pulled up to hide easily under her wig – now flow in various, zig-zagged patterns across her head and into her face. Erin admires Holtzmann’s silhouette from afar until Holtz joins her at the doorframe.  

“She asleep?” Erin’s not quite sure why she asks, already fully knowing the answer.

Holtzmann responds with a nod. “For now.”

“That’s…. _good_.”

Holtz chuckles softly at Erin’s awkwardness.

“I think she had a good time tonight.”

“Did _you_ have a good time?” Holtzmann asks.

“Oh, I-“ Erin looks down at her hands, then back up at Holtz. “Yes, I guess I did.”

Holtzmann takes a few steps forward. Erin wants to think it’s to be closer to her, but that would be _crazy_ , wouldn’t it? Holding her breath, she waits for Holtzmann to say something.

And waits.

And _waits_.

But Holtzmann simply stands there, smiling brightly at Erin behind the veil of darkness. She rocks on her feet – toes to heel, then heels to toe. On the downswing, she inches nearer, and Erin’s not quite sure what exactly Holtz is up to.

“Hey Erin?”

Wide-eyed, Erin swallows hard and slow. “Hmm?” It’s barely a word, but it comes out shaky nevertheless.

Holtzmann’s so close now that Erin swears she’s about to kiss her. Instinctively, her eyes flutter shut, but the sound of a candy wrapper in front of her face immediately snaps her back to reality.

“Want a Snickers?”

 

  **-X-X-X-X-**

 

Despite the overwhelming disappointment Erin feels over her one-on-one encounter with Holtzmann, she tries her best not to let it show on her face as she jogs around Central Park with Rosie asleep in her stroller. The swaying motion of the buggy lulls the infant – cranky all morning from their too-late excursions across New York City – into a deep sleep; if Erin can get out some of her frustrations under the guise of some exercise _and_ keep the Rugrat from turning into a full-blown monster, she certainly won’t let the opportunity slip between her fingers.

It’s not long before her brisk jog picks up speed. The brisk autumn air burns her cheeks and lungs, but Erin’s so deep in thought that she hardly notices. Tears trickle down her cheek as she runs; if anyone were to ask, she’d assuredly blame the prickling wind.

 

**-X-X-X-X-**

 

“Hey hot mama!”

Holtzmann’s greeting doesn’t exactly lift Erin’s spirits. Although she’d hoped her run would squelch her sour mood, she feels 200 calories hungrier and slightly windburned.

“Hi my Rosie-bear! Did you and Mama E have some fun today?”

“Please,” Erin barks, “don’t call me that.”

“I…” Holtzmann’s voice cracks. “Sorry?”

It isn’t right, Erin knows, to take her frustrations out on Holtz. It isn’t _her_ fault that they’re on two different wavelengths when it comes to their relationship – or lack thereof. Erin’s certainly not going to _force_ Holtzmann to feel something for her, but these quiet, intimate moments together – especially since Rosie’s appearance in their lives – make her long for something that just isn’t going to be. They can play house all they want, but that doesn’t mean it will be anything but a charade at the end of the day.

“If I did something wrong, Erin, I’m really sorry….” Holtzmann rounds the corner and picks Rosie up from where she’s tucked against Erin’s lap. Holtz starts rocking back and forth with Rosie in her arms (Erin’s convinced it’s an instinct Holtzmann doesn’t even realize she does), and for a brief moment, all the anger Erin’s feeling slips away. Like it’s impossible to feel angry while watching adorable puppy videos on repeat, it’s equally as impossible to be upset with two adorably sweet, goofy and loving girls standing in front of her.

“I’m sorry, I’m feeling a bit under the weather today,” Erin lies.

“Well why didn’t you say so? You know what the cure for the blues is?” Holtzmann asks, gasping playfully at the baby in her arms and immediately eliciting the cutest giggle imaginable. In the blink of an eye, Holtzmann’s rushing toward her with Rosie securely in her arms. She presses Rosie’s tiny little lips all over Erin’s cheek and makes loud, kissy noises as Rosie drools all over one of her adoptive mothers. After a few minutes of baby kisses – which quickly bring a huge smile to Erin’s face – there’s suddenly a very warm and very _different_ pair of lips against her cheek; Holtzmann shyly leaves a peck. “I hope you feel better, Erin.”

Erin’s stunned speechless. When Holtzmann pulls Rosie away to the kitchen for her afternoon bottle, Erin can’t help but run her fingertips over the space where Holtz’s lips were only moments before.

**Notes for the Chapter:**

> Comments make the author smile and inspire more :)


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